Known among control systems is communication arranged from the controlled object along a conventional telephone line to the control unit, for instance. In the control object there can be many sensors to switch on the message/alarm connection, such as a motion detector, burglar alarm, smoke or heat detector, thanks to which connection is switched on to the control centre. The communication can include data regarding the nature of alarm.
A system of this kind is well suited for control of objects in a fixed location, for instance objects cabled to a unit in a building, from where there is, for instance, a phone line to the control centre. On limited areas the system is applicable to control of mobile objects only by means of special arrangements.
Known as detection systems there are systems based on RSSI bearing and systems based on GSM phone cell and GSM phone net. In these cases the detected object has to have a transmitter sending signals, a detectable GMS cell or such like. They have in common that the object of detection is actively taking part in the, while containing applications serving the detection.
The detection takes place on the area of GSM base stations that have received the signals sent by the GSM cell. If there are, simultaneously, several base stations on the range area, the detection can be better focused.
The disadvantage of these detection systems is great inaccuracy. At its best, it is possible to reach an accuracy only from 300 m to 3 km, which is rather insufficient.